1. Technical Field of the Invention
The present invention relates generally to data communication and, more particularly, to output drivers utilized for data transfer.
2. Description of Related Art
A variety of output drivers are known in the art for driving data lines to transfer data. These devices are commonly referred to as output drivers, buffers, transmission drivers, bus drivers, or simply drivers, as well as other terms. High speed output drivers demand a significant portion of the overall transmitter power and tend to limit the overall performance of the entire transmission system. Typically, traditional output drivers are designed to operate with a single signaling scheme. Thus, when different communication standards are employed calling for different signaling schemes, a significant overhead may be required to meet this need.
New transmitter architectures allow a high speed output driver to operate in two popular signaling schemes or modes. One is a return-to-zero (RZ) signaling scheme and the other is a non-return-to-zero (NRZ) signaling scheme. When using traditional output drivers, separate drivers are employed, one for each scheme, if both NRZ and RZ capabilities are to be built into an integrated circuit chip. However, accommodating both NRZ and RZ schemes significantly increases chip overhead, when separate drivers are employed.
Thus, there is a need for an output driver that provides high speed data transfers in both NRZ and RZ output modes, but with reduced chip overhead to reduce power.